I've recently had a bruise appear out of nowhere on the inner side of my right arm, on the bicep. I know i havent banged it on anything. Its about 3 inch in diameter, and a dark purple color. Now whats strange is the centre of it is white, the same white as a scar. And where its white, a lump has formed. I've had it for a week now, the bruising has'nt gone down, and the lump hasnt grown, not from what i can tell anyway. Does anyone have any ideas on what it may be?

I'm going to the doctors in a week, just wondering if its a simple bruise or maybe something else.

It may be that a blood vessel has broken in your arm. This can occasionally happen without much of a hit to it. It may have been that you moved it or lifted something causing some increased pressure in the vein leading to it breaking. The vein will heal on its own without difficulty.

Bruises, especially large ones, can take several days before they begin to resolve and full resolution can take a few weeks.

If it isn't getting better it is a good idea to have it checked out, though.